High-Efficiency MicroLED Displays Enabled Through PulseForge-Assisted Die Transfer

Pranav Gavirneni, University of Waterloo

A pathway to scalable microLED mass-transfer technology utilizing a PulseForge-assisted die transfer process (PATP) was studied. PATP involves an intermediate glass carrier (IC) coated with an inorganic release layer to transfer an array of LEDs over a 150mm × 75mm area. The transferred LEDs had a 55% peak EQE.

Higher External Quantum Efficiency with Lower Current Density Injection of <10µm Pixel Size Arrays for Display Application

Yibo Liu, Hong Kong University of Science and Technology

100µm to 3µm GaN MicroLEDs were fabricated by a self-aligned process with hydroxide treatment and ALD passivation. EQE and luminance vs. current density dependence for array device and the single device were compared. Current spreading and size-dependent carrier concentration will be discussed.

Novel a-IGZO TFT Micro-LED Circuit with Improved Stability and Area Efficiency

ChanjinbPark, Seoul National University 

A novel a-IGZO TFT pixel circuit for a PWM driving microLED display is proposed. A compact structure can be achieved by eliminating the data line for the constant current generation (CCG) unit. Furthermore, the proposed circuit effectively reduces the current error rate of the CCG unit, especially at low gray levels.

Elevating the Light Output Power Density of Scaling-Down AlGaN Ultraviolet-C MicroLEDs

Feng Feng, Hong Kong University of Science and Technology 

Ultraviolet band-C (UV-C) micro-light-emitting diodes (microLEDs) with high optical power density are increasingly adopted for sterilization, solar-blind communications, and neuroscience. In this work, AlGaN UV-C microLEDs from 5um to 100um square are fabricated and characterized for light output power density and luminescence efficiency.

Inkjet-Printed Quantum-Dot Photoresist Light-Converting Layer and Photolithography Pixel Patterning for Microdisplays

Tyng-Woei Jang, National Tsing Hua University 

A specially formulated ink-jet-printed quantum-dot photoresist (QDPR) is proposed to alleviate the material losses of up to 90% encountered with conventional photolithography processes. The printed and photolithographically further patterned layer (line width 25 µm, thickness 0.95 µm) exhibits a conversion efficiency of 15.1%.

Panel Discussion: Commercial Impact of µLED Advances